49121

400 series passivation [South Carolina] 

June 23, 2008

Is nitric acid the prefered method of 400 series SS?

Rickey Phillips
finishing dept. supervisor - Startanburg, SC, USA

Hi, Rickey. Nitric vs. citric has been debated in depth several times on this site.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Rickey,
It is perhaps best to say that nitric is an approved method in the major passivation specs (ASTM A-967 [link is to spec at TechStreet], AMS-2700 [link is to spec at TechStreet]). Citric is of course also an approved method. The specs do not speak to a preference between the two, and that's about as close to an official industry standing on the matter as you can get.

Naturally there is nothing to stop you from evaluating both methods and coming to a personal preference.

Ray Kremer Stellar Solutions, Inc. Algonquin, IL, USA